Removed fixed dependencies

packages/analyzer/lib/src/summary/bazel_summary.dart

Index: packages/analyzer/lib/src/summary/bazel_summary.dart
diff --git a/packages/analyzer/lib/src/summary/bazel_summary.dart b/packages/analyzer/lib/src/summary/bazel_summary.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a7b9b880c62664c66879d09b9f1400bcd0a3a68c
--- /dev/null
+++ b/packages/analyzer/lib/src/summary/bazel_summary.dart
@@ -0,0 +1,561 @@
+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:convert';
+
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_collection.dart';
+import 'package:analyzer/src/summary/api_signature.dart';
+import 'package:analyzer/src/summary/format.dart';
+import 'package:analyzer/src/summary/idl.dart';
+import 'package:analyzer/src/summary/link.dart';
+import 'package:analyzer/src/summary/package_bundle_reader.dart';
+import 'package:analyzer/src/summary/summarize_elements.dart';
+import 'package:analyzer/src/util/fast_uri.dart';
+import 'package:convert/convert.dart';
+import 'package:crypto/crypto.dart';
+import 'package:meta/meta.dart';
+
+/**
+ * Return the [Folder] where bundles for the given [absoluteUri] should be
+ * looked for. This folder should contain corresponding `*.full.ds` files,
+ * possibly more than one one.  Return `null` if the given [absoluteUri]
+ * does not have the expected structure, so the output path cannot be computed.
+ */
+typedef Folder GetOutputFolder(Uri absoluteUri);
+
+/**
+ * Load linked packages on demand from [SummaryProvider].
+ */
+class BazelResultProvider extends ResynthesizerResultProvider {
+  final SummaryDataStore dataStore;
+  final SummaryProvider summaryProvider;
+
+  final Map<Source, bool> sourceToSuccessMap = <Source, bool>{};
+  final Set<Package> addedPackages = new Set<Package>();
+
+  factory BazelResultProvider(SummaryProvider summaryProvider) {
+    SummaryDataStore dataStore = new SummaryDataStore(const <String>[]);
+    return new BazelResultProvider._(dataStore, summaryProvider);
+  }
+
+  BazelResultProvider._(
+      SummaryDataStore dataStore, SummaryProvider summaryProvider)
+      : dataStore = dataStore,
+        summaryProvider = summaryProvider,
+        super(summaryProvider.context, dataStore) {
+    AnalysisContext sdkContext = context.sourceFactory.dartSdk.context;
+    createResynthesizer(sdkContext, sdkContext.typeProvider);
+  }
+
+  @override
+  bool hasResultsForSource(Source source) {
+    return sourceToSuccessMap.putIfAbsent(source, () {
+      List<Package> packages = summaryProvider.getLinkedPackages(source);
+      if (packages == null) {
+        return false;
+      }
+      for (Package package in packages) {
+        if (addedPackages.add(package)) {
+          dataStore.addBundle(null, package.unlinked);
+          dataStore.addBundle(null, package.linked);
+        }
+      }
+      String uriString = source.uri.toString();
+      return resynthesizer.hasLibrarySummary(uriString);
+    });
+  }
+}
+
+/**
+ * Information about a Dart package in Bazel.
+ */
+class Package {
+  final File unlinkedFile;
+  final PackageBundle unlinked;
+  final Set<String> _unitUris = new Set<String>();
+
+  PackageBundle _linked;
+
+  Package(this.unlinkedFile, this.unlinked) {
+    _unitUris.addAll(unlinked.unlinkedUnitUris);
+  }
+
+  PackageBundle get linked => _linked;
+
+  @override
+  String toString() => '$unlinkedFile';
+}
+
+/**
+ * Class that reads summaries of Bazel packages.
+ *
+ * When the client needs to produce a resolution result for a new [Source], it
+ * should call [getLinkedPackages] to check whether there is the set of
+ * packages to resynthesize resolution results.
+ */
+class SummaryProvider {
+  final ResourceProvider provider;
+  final String tempFileName;
+  final GetOutputFolder getOutputFolder;
+  final Folder linkedCacheFolder;
+  final AnalysisContext context;
+  final PackageBundle sdkBundle;
+
+  /**
+   * If `true` (by default), then linking new bundles is allowed.
+   * Otherwise only using existing cached bundles can be used.
+   */
+  final bool allowLinking;
+
+  /**
+   * See [PackageBundleAssembler.currentMajorVersion].
+   */
+  final int majorVersion;
+
+  /**
+   * Mapping from bundle paths to corresponding [Package]s.  The packages in
+   * the map were consistent with their constituent sources at the moment when
+   * they were put into the map.
+   */
+  final Map<Folder, List<Package>> folderToPackagesMap = {};
+
+  /**
+   * Mapping from [Uri]s to corresponding [Package]s.
+   */
+  final Map<Uri, Package> uriToPackageMap = {};
+
+  /**
+   * Mapping from [Package]s to corresponding [_LinkNode]s.
+   */
+  final Map<Package, _LinkNode> packageToNodeMap = {};
+
+  SummaryProvider(
+      this.provider,
+      this.tempFileName,
+      this.getOutputFolder,
+      this.linkedCacheFolder,
+      AnalysisContext context,
+      {@visibleForTesting
+          this.allowLinking: true,
+      @visibleForTesting
+          this.majorVersion: PackageBundleAssembler.currentMajorVersion})
+      : context = context,
+        sdkBundle = context.sourceFactory.dartSdk?.getLinkedBundle();
+
+  /**
+   * Return the complete list of [Package]s that are required to provide all
+   * resolution results for the given [source].
+   *
+   * The same list of packages is returned for the same [Source], i.e. always
+   * the full list, not a difference with a previous request.  It is up to the
+   * client to decide whether some of the returned packages should be excluded
+   * as already mixed into a resynthesizer.
+   *
+   * If the full set of packages cannot be produced, for example because some
+   * bundles are not built, or out of date, etc, then `null` is returned.
+   */
+  List<Package> getLinkedPackages(Source source) {
+    // Find the node that contains the source.
+    _LinkNode node = _getLinkNodeForUri(source.uri);
+    if (node == null) {
+      return null;
+    }
+
+    // Compute all transitive dependencies.
+    node.computeTransitiveDependencies();
+    List<_LinkNode> nodes = node.transitiveDependencies.toList();
+    nodes.forEach((dependency) => dependency.computeTransitiveDependencies());
+
+    // Fail if any dependency cannot be resolved.
+    if (node.failed) {
+      return null;
+    }
+
+    // Read existing cached linked bundles.
+    for (_LinkNode node in nodes) {
+      _readLinked(node);
+    }
+
+    // Link new packages, if allowed.
+    if (allowLinking) {
+      _link(nodes);
+    }
+
+    // Create successfully linked packages.
+    return nodes
+        .map((node) => node.package)
+        .where((package) => package.linked != null)
+        .toList();
+  }
+
+  /**
+   * Return the [Package] that contains information about the source with
+   * the given [uri], or `null` if such package does not exist.
+   */
+  @visibleForTesting
+  Package getUnlinkedForUri(Uri uri) {
+    return uriToPackageMap.putIfAbsent(uri, () {
+      Folder outputFolder = getOutputFolder(uri);
+      if (outputFolder != null) {
+        String uriStr = uri.toString();
+        List<Package> packages = _getUnlinkedPackages(outputFolder);
+        for (Package package in packages) {
+          if (package._unitUris.contains(uriStr)) {
+            return package;
+          }
+        }
+      }
+      return null;
+    });
+  }
+
+  /**
+   * Return the hexadecimal string of the MD5 hash of the contents of the
+   * given [source] in [context].
+   */
+  String _computeSourceHashHex(Source source) {
+    String text = context.getContents(source).data;
+    List<int> bytes = UTF8.encode(text);
+    List<int> hashBytes = md5.convert(bytes).bytes;
+    return hex.encode(hashBytes);
+  }
+
+  /**
+   * Return the name of the file for a linked bundle, in strong or spec mode.
+   */
+  String _getLinkedName(String hash) {
+    if (context.analysisOptions.strongMode) {
+      return 'linked_$hash.ds';
+    } else {
+      return 'linked_spec_$hash.ds';
+    }
+  }
+
+  /**
+   * Return the node for the given [uri], or `null` if there is no unlinked
+   * bundle that contains [uri].
+   */
+  _LinkNode _getLinkNodeForUri(Uri uri) {
+    Package package = getUnlinkedForUri(uri);
+    return packageToNodeMap.putIfAbsent(package, () {
+      if (package == null) {
+        return null;
+      }
+      return new _LinkNode(this, package);
+    });
+  }
+
+  /**
+   * Return all consistent unlinked [Package]s in the given [folder].  Some of
+   * the returned packages might be already linked.
+   */
+  List<Package> _getUnlinkedPackages(Folder folder) {
+    List<Package> packages = folderToPackagesMap[folder];
+    if (packages == null) {
+      packages = <Package>[];
+      try {
+        List<Resource> children = folder.getChildren();
+        for (Resource child in children) {
+          if (child is File) {
+            String packagePath = child.path;
+            if (packagePath.toLowerCase().endsWith('.full.ds')) {
+              Package package = _readUnlinkedPackage(child);
+              if (package != null) {
+                packages.add(package);
+              }
+            }
+          }
+        }
+      } on FileSystemException {}
+      folderToPackagesMap[folder] = packages;
+    }
+    return packages;
+  }
+
+  /**
+   * Return `true` if the unlinked information of the [bundle] is consistent
+   * with its constituent sources in [context].
+   */
+  bool _isUnlinkedBundleConsistent(PackageBundle bundle) {
+    try {
+      // Compute hashes of the constituent sources.
+      List<String> actualHashes = <String>[];
+      for (String uri in bundle.unlinkedUnitUris) {
+        Source source = context.sourceFactory.resolveUri(null, uri);
+        if (source == null) {
+          return false;
+        }
+        String hash = _computeSourceHashHex(source);
+        actualHashes.add(hash);
+      }
+      // Compare sorted actual and bundle unit hashes.
+      List<String> bundleHashes = bundle.unlinkedUnitHashes.toList()..sort();
+      actualHashes.sort();
+      return listsEqual(actualHashes, bundleHashes);
+    } on FileSystemException {}
+    return false;
+  }
+
+  /**
+   * Link the given [nodes].
+   */
+  void _link(List<_LinkNode> nodes) {
+    // Fill the store with bundles.
+    // Append the linked SDK bundle.
+    // Append unlinked and (if read from a cache) linked package bundles.
+    SummaryDataStore store = new SummaryDataStore(const <String>[]);
+    store.addBundle(null, sdkBundle);
+    for (_LinkNode node in nodes) {
+      store.addBundle(null, node.package.unlinked);
+      if (node.package.linked != null) {
+        store.addBundle(null, node.package.linked);
+      }
+    }
+
+    // Prepare URIs to link.
+    Map<String, _LinkNode> uriToNode = <String, _LinkNode>{};
+    for (_LinkNode node in nodes) {
+      if (!node.isReady) {
+        for (String uri in node.package.unlinked.unlinkedUnitUris) {
+          uriToNode[uri] = node;
+        }
+      }
+    }
+    Set<String> libraryUris = uriToNode.keys.toSet();
+
+    // Perform linking.
+    Map<String, LinkedLibraryBuilder> linkedLibraries =
+        link(libraryUris, (String uri) {
+      return store.linkedMap[uri];
+    }, (String uri) {
+      return store.unlinkedMap[uri];
+    }, context.declaredVariables.get, context.analysisOptions.strongMode);
+
+    // Assemble newly linked bundles.
+    for (_LinkNode node in nodes) {
+      if (!node.isReady) {
+        PackageBundleAssembler assembler = new PackageBundleAssembler();
+        linkedLibraries.forEach((uri, linkedLibrary) {
+          if (identical(uriToNode[uri], node)) {
+            assembler.addLinkedLibrary(uri, linkedLibrary);
+          }
+        });
+        List<int> bytes = assembler.assemble().toBuffer();
+        node.package._linked = new PackageBundle.fromBuffer(bytes);
+        _writeLinked(node, bytes);
+      }
+    }
+  }
+
+  /**
+   * Attempt to read the linked bundle that corresponds to the given [node]
+   * with all its transitive dependencies.
+   */
+  void _readLinked(_LinkNode node) {
+    String hash = node.linkedHash;
+    if (!node.isReady && hash != null) {
+      String fileName = _getLinkedName(hash);
+      File file = linkedCacheFolder.getChildAssumingFile(fileName);
+      // Try to read from the file system.
+      if (file.exists) {
+        try {
+          List<int> bytes = file.readAsBytesSync();
+          node.package._linked = new PackageBundle.fromBuffer(bytes);
+        } on FileSystemException {
+          // Ignore file system exceptions.
+        }
+      }
+    }
+  }
+
+  /**
+   * Read the unlinked [Package] from the given [file], or return `null` if the
+   * file does not exist, or it cannot be read, or is not consistent with the
+   * constituent sources on the file system.
+   */
+  Package _readUnlinkedPackage(File file) {
+    try {
+      List<int> bytes = file.readAsBytesSync();
+      PackageBundle bundle = new PackageBundle.fromBuffer(bytes);
+      // Check the major version.
+      if (bundle.majorVersion != majorVersion) {
+        return null;
+      }
+      // Check for consistency, and fail if it's not.
+      if (!_isUnlinkedBundleConsistent(bundle)) {
+        return null;
+      }
+      // OK, use the bundle.
+      return new Package(file, bundle);
+    } on FileSystemException {}
+    return null;
+  }
+
+  /**
+   * Atomically write the given [bytes] into the file in the [folder].
+   */
+  void _writeAtomic(Folder folder, String fileName, List<int> bytes) {
+    String filePath = folder.getChildAssumingFile(fileName).path;
+    File tempFile = folder.getChildAssumingFile(tempFileName);
+    tempFile.writeAsBytesSync(bytes);
+    tempFile.renameSync(filePath);
+  }
+
+  /**
+   * If a new linked bundle was linked for the given [node], write the bundle
+   * into the memory cache and the file system.
+   */
+  void _writeLinked(_LinkNode node, List<int> bytes) {
+    String hash = node.linkedHash;
+    if (hash != null) {
+      String fileName = _getLinkedName(hash);
+      _writeAtomic(linkedCacheFolder, fileName, bytes);
+    }
+  }
+}
+
+/**
+ * Information about a single [Package].
+ */
+class _LinkNode {
+  final SummaryProvider linker;
+  final Package package;
+
+  bool failed = false;
+  Set<_LinkNode> transitiveDependencies;
+
+  List<_LinkNode> _dependencies;
+  String _linkedHash;
+
+  _LinkNode(this.linker, this.package);
+
+  /**
+   * Retrieve the dependencies of this node.
+   */
+  List<_LinkNode> get dependencies {
+    if (_dependencies == null) {
+      Set<_LinkNode> dependencies = new Set<_LinkNode>();
+
+      void appendDependency(String uriStr) {
+        Uri uri = FastUri.parse(uriStr);
+        if (!uri.hasScheme) {
+          // A relative path in this package, skip it.
+        } else if (uri.scheme == 'dart') {
+          // Dependency on the SDK is implicit and always added.
+          // The SDK linked bundle is precomputed before linking packages.
+        } else if (uri.scheme == 'package') {
+          _LinkNode packageNode = linker._getLinkNodeForUri(uri);
+          if (packageNode == null) {
+            failed = true;
+          }
+          if (packageNode != null) {
+            dependencies.add(packageNode);
+          }
+        } else {
+          failed = true;
+        }
+      }
+
+      for (UnlinkedUnit unit in package.unlinked.unlinkedUnits) {
+        for (UnlinkedImport import in unit.imports) {
+          if (!import.isImplicit) {
+            appendDependency(import.uri);
+          }
+        }
+        for (UnlinkedExportPublic export in unit.publicNamespace.exports) {
+          appendDependency(export.uri);
+        }
+      }
+
+      _dependencies = dependencies.toList();
+    }
+    return _dependencies;
+  }
+
+  /**
+   * Return `true` is the node is ready - has the linked bundle or failed (does
+   * not have all required dependencies).
+   */
+  bool get isReady => package.linked != null || failed;
+
+  /**
+   * Return the hash string that corresponds to this linked bundle in the
+   * context of its SDK bundle and transitive dependencies.  Return `null` if
+   * the hash computation fails, because for example the full transitive
+   * dependencies cannot computed.
+   */
+  String get linkedHash {
+    if (_linkedHash == null && transitiveDependencies != null && !failed) {
+      ApiSignature signature = new ApiSignature();
+      // Add all unlinked API signatures.
+      List<String> signatures = <String>[];
+      signatures.add(linker.sdkBundle.apiSignature);
+      transitiveDependencies
+          .map((node) => node.package.unlinked.apiSignature)
+          .forEach(signatures.add);
+      signatures.sort();
+      signatures.forEach(signature.addString);
+      // Combine into a single hash.
+      appendDeclaredVariables(signature);
+      _linkedHash = signature.toHex();
+    }
+    return _linkedHash;
+  }
+
+  /**
+   * Append names and values of all referenced declared variables (even the
+   * ones without actually declared values) to the given [signature].
+   */
+  void appendDeclaredVariables(ApiSignature signature) {
+    Set<String> nameSet = new Set<String>();
+    for (_LinkNode node in transitiveDependencies) {
+      for (UnlinkedUnit unit in node.package.unlinked.unlinkedUnits) {
+        for (UnlinkedImport import in unit.imports) {
+          for (UnlinkedConfiguration configuration in import.configurations) {
+            nameSet.add(configuration.name);
+          }
+        }
+        for (UnlinkedExportPublic export in unit.publicNamespace.exports) {
+          for (UnlinkedConfiguration configuration in export.configurations) {
+            nameSet.add(configuration.name);
+          }
+        }
+      }
+    }
+    List<String> sortedNameList = nameSet.toList()..sort();
+    signature.addInt(sortedNameList.length);
+    for (String name in sortedNameList) {
+      signature.addString(name);
+      signature.addString(linker.context.declaredVariables.get(name) ?? '');
+    }
+  }
+
+  /**
+   * Compute the set of existing transitive dependencies for this node.
+   * If any dependency cannot be resolved, then set [failed] to `true`.
+   * Only unlinked bundle is used, so this method can be called before linking.
+   */
+  void computeTransitiveDependencies() {
+    if (transitiveDependencies == null) {
+      transitiveDependencies = new Set<_LinkNode>();
+
+      void appendDependencies(_LinkNode node) {
+        if (transitiveDependencies.add(node)) {
+          node.dependencies.forEach(appendDependencies);
+        }
+      }
+
+      appendDependencies(this);
+      if (transitiveDependencies.any((node) => node.failed)) {
+        failed = true;
+      }
+    }
+  }
+
+  @override
+  String toString() => package.toString();
+}